The present invention relates generally to gas turbine engines, and, more specifically, to exhaust nozzles therefor.
In a typical gas turbine engine configured for powering an aircraft in flight to supersonic velocities, an afterburner or augmenter is provided for burning additional fuel and providing additional thrust from the engine. Since the aircraft has an extensive flight envelope requiring different power requirements from the engine, the exhaust nozzle is typically variable for maximizing engine efficiency and performance over the flight envelope. The exhaust nozzle typically converges in flow area to a throat of minimum flow area from which the exhaust gases may expand. In a typical engine, a diverging nozzle extends aft from the converging nozzle to create a combined converging-diverging (CD) exhaust nozzle.
The converging and diverging nozzles are typically formed of a plurality of circumferentially adjoining primary and secondary exhaust flaps joined together with cooperating outer flaps in a conventional four-bar linkage. Suitable actuators are provided for adjusting the kinematics of the exhaust nozzle to vary the flow areas of the converging and diverging nozzle portions thereof as required during the flight envelope.
Accordingly, the typical CD exhaust nozzle is an assembly of many components which must be suitably actuated, sealed, and cooled for effective operation. However, this is obtained with an increase in complexity, weight, and cost of the engine due to the additional components required therefor and associated manufacturing costs.
Fixed geometry CD nozzles are known and may be used for a limited range of engine variability. However, a relatively complex shape of fixed nozzles typically requires relatively complex manufacturing processes and equipment in the form of expensive dies, forms, and tooling specifically configured therefor.
Accordingly, an improved fixed geometry CD exhaust nozzle having a simple construction and process of manufacture are desired for reducing engine complexity, weight, and cost.